At first, I wasn't a big fan of the Mk4 GTI's. I had a couple of test-drives in the 2.0 8v's and they just felt a bit heavy and sluggish.
Maybe it was just the particular cars I'd driven, but my Mk4 1.8 20v wipes the floor with them - I'm sure the Mk4 turbo's are even better! To be honest, I don't really know why VW stopped making the 1.8 GTIs.

My bro' used to have a Mk1 GTI, and that was a loads of fun. I must admit that my Mk4 doesn't have quite so much poke (cos its heavier), but once you get over about 3500 revs the 1.8 Mk4 really starts to shine.

but... If I could find a good example of a Mk1, I'd prefer that (for fun factor) any day.